Yoga is a Sanskrit word. It can be translated as “Union”. In the sense: union between body and spirit. It could also be interpreted as union with the “One” (the Brahman). All aspects of yoga have as roots these two principles of union. Yoga’s ultimate goal is to attain liberation of the mind by being spiritually connected to the universal one. In Sanskrit, this liberation is called “Moksha”. It is the liberation of the life cycle of reincarnation due to the Karma (the law of cause and consequence.) Yoga origin is very old. It is maybe as old as human or even older. Indeed, some archaeologists have found evidences of a spiritual tradition in pre-human being, our ancestors. They probably practiced spiritual meditation, the origin of yoga. The first writing about Yoga, is found in the Rig Veda, the oldest texts from India (around 2000 B.C, one of the oldest texts in the world). It should be added that these texts are only the transcription of even older oral tradition dating from maybe 7000 or 10000 years ago.
The main scripture describing the yoga and its different models is the Bhagavad-Gîtâ, It describes all the different way to attain the Brahman, the union with God. It shows four principal methods of Yoga: The Raja Yoga which is the psycho-physical path of illumination, the Karma Yoga which is the path in which the person give without wanting reward. There is also the path of knowledge: the Jnana Yoga and the path of love and devotion to God: the Bhakti Yoga. The most known path of yoga is the Hatha yoga which was invented long after the first Yoga texts. It have been created around the 15th century in India. In fact, it is a kind of Raja Yoga, the only real difference is the order in which the yogi attain liberation. In Raja Yoga, the purification of the mind come first and the body second. In Hatha yoga it is the reverse order.
Many studies have been done on the yogis and the Yoga in general to explain the spectacular benefit it gives to the health. Some yogi are able to be in a meditation state during more than 3 months. During this state they seem almost dead, their breathing is so slow that it is really difficult to detect it. They have the capacities to live in a room without oxygen during 10 minutes or more. Also their brain seem to be working in more efficient way because all the parts of the brain, seem working together. But not only yogis (yoga expert) have benefit from yoga. Studies have shown that anybody starting Hatha yoga (the most studied) get quickly benefit from their daily physical exercises. It is lot more healthy that modern gymnastic which produce too much lactic acid for example. Yoga is the best way to keep an healthy body.